Suction roll counter-deflector



Sept. 20, 1966 E. J. JUSTUS 3,273,492

SUCTION ROLL COUNTER-DEFLECTOR Filed Oct. 16, 1963 2 Sheets-Sheet 1 III! W INVENTOR. Z@a"z l Jzzsags A TTORNElaS United States Patent3,273,492 SUCTION ROLL CUUNTER-DEFLECTQR Edgar J. Justus, Beloit, Wis,assignor to Beloit Qorporation, Beloit, Wis, a corporation of WisconsinFiled Oct. 16, 1963, Ser. No. 316,711 18 Claims. (Cl. 100-90) Thisinvention relates to apparatus for mounting a roll the centroidal axisof which is subject to deflection and more particularly relates toapparatus for mounting a suction roll which is subjected to a loadtending to effect central deflection of the roll axis.

Although the instant invention may be useful in a number of arts,including textile treating, it is particularly useful in the papermakingart and will be described primarily in connection therewith. In general,the instant invention relates to apparatus for mounting a roll shellhaving a substantial length-to-diameter ratio and whose centroidal axisis subject to deflection in response to the loads applied to the shellduring use.

In paper machines there are a number of different types of rolls ofsubstantial size (i.e., substantial length) which are subjected to loadstending to deflect such rolls generally. For example, in press couples,calender stacks, etc., the web passes through a nip between a pair ofrolls at which the web is subjected to pressures. The pressure thusapplied at such nip tends to load the rolls defining the nip and todeflect the axes of these rolls, thereby causing non-uniformcross-machine nip loads.

Another example of a roll shell having a substantial length-to-diameterratio is a suction roll which includes a perforated revolving roll shellover which a moist web passes and is dewatered due to a vacuum conditionwhich exists within the roll shell. This shell is also generally subjectto deflection due to the various loads acting thereon, which may includethe vacuum applied to the shell and the weight of the shell and whichmay also include, when the suction roll is used in conjunction withanother roll to define a press couple forming a press nip to squeeze theweb, an additional load due to the nip loading.

If one of the rolls defining a nip is backed up by other rolls or othermeans, its tendency to deflect away from the nip is reduced or may becompletely overcome so that it is defected in the direction of the nip.On the other hand, certain press rolls and, for example, a suction rollmay not be provided with back up means and the pressures or loads thusapplied thereto tend to deflect the same centrally. Such deflectionresults in undesirable and/or nonuniform application of forces acrossthe roll, or across the nip, and other undesirable operating features.

Deflection of roll shells is often corrected in paper machines bycrowning of the shell. Crowning requires accurate and expensivefinishing of the roll surface so as to obtain a slightly greater rolldiameter in the central portion of the roll and furthermore suchcrowning is carried out on the basis of a predetermined set of forceconditions and may not be satisfactory for operating under a differentset of force conditions. In addition, a crowned roll will have asomewhat greater circumference in the crowned region (usually at thecenter) than at the uncrowned regions of the roll, and this results in aslightly greater surface speed at the outer periphery of the roll in thecrowned region. Such surface speed differences in the operation ofcertain nips result in undesirable operating characteristics in manyinstances. It will thus be seen that crowning of rolls often does notafford satisfactory operation for many different types of operat ingconditions.

Another method of correcting for roll deflection involves the use offorce couples for applying internal 3,273,492 Patented Sept. 20, 1966counter-deflection moments to the shell in response to the applicationof the load to the shell in such a manner as to more or lessautomatically resist or minimize deflection of the roll when it issubjected to various loads. General concepts as Well as more specificaspects of this type of roll shell mounting arrangement are described inEdgar J. Justus US. Patents 3,097,590 and 3,097,591 which are owned bythe assignee of the instant invention and which disclosures areincorporated herein by reference.

The application of internal counter-deflection moments to the shell tominimize deflection presents peculiar problems in the case of suctionrolls, however. Due to the drilling pattern of the perforations of asuction shell its bending efficiency may be as little as 40% to 50% ofthe efliciency of an undrilled shell. This unavoidable reduction inbending efficiency therefore generally results in a thicker andconsequently more expensive suction roll shell.

The instant invention affords a unique improvement in roll shellmounting structures and particularly suction rolls which embody thebasic concepts of counter-deflection moments heretofore mentioned. Incertain rolls, for example, suction rolls, a roll shell may be carriedon a shaft or beam member which extends through the shell. In the caseof a suction roll, the roll shell may comprise a perforate portion fordewatering the web and the shaft or beam member is non-rotating andincludes a suction box or gland formed integrally therewith to alignwith the perforate portion of the shell.

Since the bending efficiency of a perforate suction roll shell isappreciably reduced as compared to an imperforate shell, the necessarycounter-deflection should be attained with minimum bending moment,particularly in the center of the shell. Such reduction in bendingmoment would, of course, permit the utilization of a thinner andconsequently less expensive roll shell.

The present invention contemplates the utilization of novel mountingstructure for appreciably reducing the bending moment of the roll shellfor any given load applied thereto as a result, for example, of nippressure, applied vacuum or weight of the shell. Briefly, the journalsof the roll shell are extended and forced generally .in a directionopposite to the direction of the load which is applied to the shellthereby urging the center portion of the shell in a direction oppositeto the direction of the applied loads. This mounting arrangement resultsin a drastic reduction of the bending moment in the center of the shell.In certain cases this reduction may be as high as 20 to 30%. Althoughthe bending moment on the shell journals will generally increase, thejournals are not drilled and are, therefore, fully capable of taking theadditional load.

It is, therefore, an important object of the present invention toprovide an improved roll mounting structure.

It is another object of the instant invention to provide an improvedarrangement for mounting a roll shell having a substantiallength-to-diameter ratio .in order to correct for tendencies towarddeflection of the roll shell axis as a result of loads applied thereto.

Yet another object of the present invention is to provide a roll shellfor a suction roll assembly having a perforate center portion and asubstantial length-to-diameter ratio, and whose centroidal axis issubject to deflection in response to a load applied to the shell,axially aligned shaft means in the shell and in spaced relation theretofor rotatably mounting the shell, imperforate journal portions at eachend of the roll shell, bearing means on the shaft means and engaging thejournal portions of the shell for maintaing the shell in axially spacedrelation to the shaft means, and force imposing means acting on thejournals and axially spaced relative to the bearing means for impartingcounter-deflection force cou- 'ice p le to the shell while minimizingbending moments in the shell, particularly in the perforate centerportion thereof.

Many other features, advantages and additional objects of the presentinvention will become manifest to those versed in the art upon makingreference to the detailed description which follows and the accompanyingsheets of drawings in which a preferred structural embodiment of theinventive principles herein disclosed is shown by way of illustrativeexample.

On the drawings:

FIGURE 1 is a somewhat diagrammatic elevational illustration of a rollshell mounting structure constructed in accordance with the principlesof the present invention and showing portions of the structure insection;

FIGURE 2 is a fragmentary essentially diagrammatic view illustrating thesuction roll shell and the press roll of FIGURE 1 arranged innip-defining relation to provide a press couple;

FIGURE 3 is essentially a force diagram illustrating loads and forcesapplied to a conventional suction roll and includes a formulation of themaximum bending moment acting on the shell as a result of the appliedloads and forces;

FIGURE 4 is also essentially a force diagram illustrating loads andforces applied to an anti-deflection suction roll constructed inaccordance with the principles of the present invention and includes aformulation of the maximum bending moment acting on the shell as aresult the improved mounting arrangement of the shell; and

FIGURE 5 is an essentially diagrammatic illustration of deflectioncurves involved in a consideration of the instant invention.

As shown on the drawings:

In FIGURE 1, it will be seen that the assembly of the instant invention,indicated generally by the reference numeral 10, is adapted to mount asuction roll assembly 11 including a roll shell 12 having a substantiallength-todiameter ratio. A pressure roll 13 may conveniently be mountedin nip defining relation with the roll shell 12 for providing a presscouple having a press nip as at 14. Journal means 16 are provided forrotatably mounting the press roll 13 and suitable apparatus may beprovided for applying a load to the press roll to pressurize the nip 14,for example, pressurized hydraulic cylinder means (not shown).

The nip defining relationship between the press roll 13 and the suctionroll shell 12 is also illustrated in FIG- URE 2 wherein is shown a web Win a moistened condition as supplied, for example, from the wire formingsection of a paper-making machine to pass through the pressurized nip14. In order to dewater the web as it passes through the nip a suctionbox or gland 17 is housed within the shell 12 in spaced relation theretoand it will be appreciated that during operation a suction chamber 18defined by the suction box 17 is maintained at a subatmospheric orvacuum condition in order to withdraw water from the web into thechamber. To permit access of the water through the shell 12 into thechamber 18, a plurality of circumferentially and axially spacedperforations as at 19 are formed in the shell 12 to extend radiallytherethrough and an upper portion 20 of the suction box 17 immediatelyadjacent the pressurized nip 14 defines an axially extending slot 21 forcommunicating the chamber 18 with the perforations 19 and therefore withthe nip 14.

The suction box 17 is non-rotatable, and in order to insure that thevacuum condition which exists within the chamber 18 acts only on thatportion of the shell 12 adjacent the nip 14, a pair of axially extendingseals 22 are carried by upper shoulders 23 of the suction box to isolatethat portion of the inner periphery of the shell 12 from the remainderthereof, thereby providing that that portion of the shell 12 immediatelyadjacent the nip 14 will be in communication exclusively with thechamber 18 and thereby have a suction force applied thereto.

In order to provide for varying axial alignment and spacing between theshell 12 and the movable suction box 17 as various loads are applied tothe shell to cause deflection thereof, the seals 22 may constitute anysuitable resilient material, such as rubber, such that the suction areaof the roll defined by the seals will remain under a vacuum conditionregardless of deflection of the shell 12.

It will be appreciated that the roll shell 12 of FIGURE 1 has a lengthwhich exceeds by many times its diameter, and whose centroidal axisdefines a straight line (indicated at C-12 in FIGURE 5) in a completelyunloaded condition of the shell. That is, the axis C-1-2 is a centerline for the shell 12 when the shell is not subjected to any loadingforces whatsoever, including the load of its own weight. Practicallyspeaking, however, the shell 12 is always subjected to a load across itsentire width. This load is equal to at least the load of the weight ofthe shell, but of course in operation this load may be increased by theload applied 'by the press roll 13 and the effective load applied by thevacuum condition in the suction chamber 18, both of which act acrosssubstantially the entire width of the shell 12. Generally, any load orany combination of loads acting on the shell '12 are uniformlydistributed over the width of the shell to cause a deflection in theaxis of the shell to a position indicated in exaggerated form in FIGURE5 by the dashed line DD-12.

The actual deflection of any given roll shell, of course, depends uponmany factors including the length-to-diameter ratio of the shell, theload or combination of loads applied to the shell, the thickness of theshell, the material of construction of the shell as well as the mountingarrangement of the shell, among others.

In FIGURE 1 that portion of the width of the shell across which theperforations are formed is indicated at 23. In conventional suction rollshells the perforated por tion extends substantially across the entirewidth of the shell but in the embodiment illustrated in FIGURE 1 theperforate portion 23, while comprising a substantial percentage of thewidth of the shell 12, does not extend to the ends of the shell asindicated at 24 and 26.

At each end of the perforate portion 23, that is, between the perforateportion and the shell ends 24 and 26 respectively, is formed an axiallyextending tubularly shaped reduced diameter imperforate journal portionas at 27 and 28. The inboard ends of journals 27 and 28, that is, theends thereof that are situated in the direction of the center of thewidth of the shell 12, are joined to the enlarged diameter perforateportion 23 by means of a circumferentia-lly continuous radiallyextending member thereof as at 25.

It is important to note that the invention is directed to the control ofdeflection in perforate suction roll shells which have certain generalcharacteristics which make such control particularly diflicult. Forexample, such shells may have a radial thickness of from perhaps to 2inches; for varying stiffness in the shell; but in any case thelength-to-diameter ratio of the perforate portion of the shell alone iswithin the range of about 6:1 to 12:1 and the average open area (i.e.total area of the perforations divided by total peripheral area of theperforate position of the shell) is about 15% to 40% so that the rollshell is particularly responsive to loads. In the instant invention theimperforate end portions (the portions M, M in FIGURE 4) have lengthssuflicient for the application of the desired force couple thereto; andas compared to the central perforate portion (N of FIG- URE 4) the ratioof the lengths of M :N is Within the range of 1:10 to 1:6.

Additional details of the construction of the roll shell '12 will bediscussed hereinafter, but it is important to note that the embodimentof the roll shell illustrated in FIGURE 1 and which is constructed inaccordance with the principles of the present invention difi'ers fromthe conventional suction roll 12 in that it comprises. a pair of journalportions, and in the embodiment illustrated a reduced diameterimperforate journal portion is formed at each end of the perforateportion, at which the bending efficiency of the roll shell issubstantially and unavoidably reduced because of the necessary drilledperforations.

As in the case of a conventional suction roll assembly, the suction box17 shown in FIGURE 1 is formed integrally with and comprises the centerportion of a center beam or shaft 29 which is housed within the tubularroll shell 12 and which extends outwardly therefrom at the end-s thereofas at 30 and 31. Opposed end portions 32 and 33 of the beam 29 maypreferably be cylindrically shaped and one end portion as at 33 may beformed with a bore as at 34 formed therein and extending therethroughfor communicating the suction chamber 18 of the suction box 17 with asuitable vacuum producing means, such as a vacuum pump (not shown). Theopposite end portion 32 may comprise a solid member and both of the endportions may be immovably supported by means of a fixed support memberas illustrated at 36.

In accordance with the principles of the present invention the rollshell 12 may be supported for rotation by means of the beam or shaft 29and to this end a pair of bearing members 37 and 3*? are mountedrespectively on the end portions 32 and 33 of the shaft 29 to engage thejournal portions 27 and 28 inboardly of their respective ends 24 and 26.In addition to providing for rotation of roll shell 12, the bearingmembers perform the additional function of maintaining the shell i 2 andthe beam 29 in coaxially spaced relation.

It will be appreciated that the beam 29 is also subject to deflection inresponse to loads to which it may be subjected, which may include ofcourse the weight of the beam itself and also the load imposed thereonby the roll shell 12. Other factors, of course, enter into thedeflection characteristics of the beam, such as the length-to-diameterratio, the materials of construction and the other factors mentionedheretofore in connection with the deflection characteristics of the rollshe'll.

It is not necessary, of course, that the roll shell 12 and the beam 29have similar deflection characteristics and preferably in this respectthey are quite different. In a preferred embodiment of the invention therigidity of the beam 29, that is, its inherent resistance to deflection,is greater than the corresponding inherent resistance to deflection ofthe roll shell 12 so that in the event that a load is imposed upon theroll shell its inherent resistance to deflection will yieldsubstantially to the greater inherent resistance of the shaft 29, thatis, although the shell may deflect relatively substantially, the beamwill deflect very little or not at all.

Referring to FIGURE 3, the various loads imposed upon a conventionalsuction roll shell are illustrated as acting at various locations alongthe width of the shell. The perforated portion of the conventionalsuction roll shell 39, which essentially comprises the entire Width ofthe shell, is indicated by the reference character N which representsthe width of the shell and may conveniently be expressed in terms oflineal inches of width. The load applied to the shell, which maycomprise the weight of the shell, the action of the vacuum imposedthereon at the suction area thereof and the force applied by a pressroll cooperating with the shell to from a press couple, is indicated bythe reference L and since this composite load or any separate componentthereof acts uniformly across the entire width of the shell, the load Lmay be expressed in terms of pounds per linear inch of shell width.Since a conventional suction roll shell is generally supported on itsassociated beam only at the ends of the shell, the oppositely actingsupporting forces at the ends of the shell are equal to each other asindicated at reference characters R and may conveniently be expressed interms of pounds of force.

The maximum bending moment to which a conventional suction roll shell issubjected in operation may be de- 6 fined by the equation indicated inFIGURE 3 which reads as follows:

Maximum bending moment (R N/2)(L N/2 N/4) Where:

L=composite applied load acting uniformly across width of shell, lbs.per lineal inch N=width of shell=-width of perforated portion of shell,inches R=equal forces acting against load L at shell support members,lbs.

To illustrate the maximum bending moment to which a conventional suctionroll shell 39 is subjected in accordance with the above equation, assumethat the composite applied load L equals 50 lbs. per inch and the shellwidth N equals 200 inches. The opposing forces R will then equal 5,000lbs. and the maximum bending moment of the shell can be calculated asfollows:

Maximum bending moment =5,000 200-:-250 l00 50 =250,000 inch-lbs.

As will become apparent hereinafter the improved roll shell mountingmeans of the present invention not only acts to cause counter-deflectionof the roll shell to partially offset and compensate for the deflectionresulting from the applied load but also performs the advantageousfunction of actually decreasing the maximum bending moment to which theperforated portion of the shell is subjected, thereby permitting theutilization of a thinner and less expensive shell.

Referring again to FIGURE 1, it will be noted that at each of theoutboard end portions of journals 27 and 28 there is mountedrespectively thereon a bearing member as indicated at 40 and 41 whichcan be effectively utilized to impose a force at the end of eachjournal, thereby providing a force couple in conjunction with thecorresponding axially spaced bearing members 37 and 38. In effect,bearing members 37 and 38 act as fulcrum points for two force couples,one of which is the force couple provided by the load applied to theroll shell and which acts effectively at the center point across thewidth of the shell, and the second of which is provided by a forceacting on the axially spaced bearing members 40 and 41. Generally themost advantageous utilization of bearing members 40 and 41 occurs whenforces are imposed thereon which act in a direction similar to thedirection of the composite load acting upon the roll shell 12 which, inthe illustrated embodiment, lies in a vertically downward direction.Thus, means are provided for imposing a downward force on each of thebearing members 40 and 41 and such force imposing means may convenientlytake the form of pressurized fluid operated hydraulic cylindersillustrated diagrammatically at 42 and 43, one end of which as at 44engages a corresponding bearing member and another end of which as at 46is connected to and immovably supported by a fixed support member, .forexample, members 36.

The advantages of the improved mounting structure of FIGURE 1 can beexemplified by making advantageous reference to FIGURE 4 wherein isillustrated'diagrammatically the roll shell 12 of FIGURE 1 being actedupon by the composite applied load L acting across the entire width ofthe perforate portion as at N. As opposed to the conventional roll shellillustrated in FIGURE 3, the anti-deflection roll shell of the presentinvention as illustrated in FIGURE 4 comprises the journal portions 27and 28 extending from the ends thereof. It will be assumed that theaxial position of the forces R corresponds with the axial positioning ofthe bearing members 37 and 38, the forces R comprising the restrainingforce acting upon the shell 12 through the bearing members 37 and 38.The reference character M" indicates the axial displace ment betweencorresponding bearing members 37 and 40 and 38 and 41, such displacementbeing equal to the width of journal members 27 and 23 convenientlyexpressed in terms of lineal inches. Forces indicated by the referencecharacters S indicate the forces imposed respectively on bearing members40 and 41 by the force Imposing means or hydraulic cylinders 42 and 43.

In order to exemplify the advantageous reduction in maximum bendingmoment provided by the novel mounting arrangement of the presentinvention, assume that the composite load L acting on the roll shell 12of FIGURE 4 is equal to the load L of FIGURE 3, that is, 50 lbs. perlineal inch. In addition, assume that a force S equal to 2,000 lbs. isimposed upon journal portions 27 and 28 in the same direction as theload L is imposed upon the roll shell 12. The restraining or oppositeforces R would then each equal s 200+2 2000 +2=7000 lbs.

The maximum bending moment at the center of the shell 12 can becalculated by means of the equation illustrated in FIGURE 4, and in theassumed example given, is as follows:

Maximum bending moment =(R N/2)(L N/2 N/4) 200/4)[2000(200/2+25)]=200,000 in.-lbs.

Where M: distance between R and 8:25" S=force imposed at bearing members42 and 43 =2,000 lbs.

It will be apparent, therefore, that in the event that the load L isgiven the same value for the conventional roll shell arrangement ofFIGURE 3 and the anti'deflec- :ion roll shell arrangement of FIGURE 4,the maximum bending moment of the center of the roll shell 12 of FIGURE4, constructed and mounted in accordance with ;he principles of thepresent invention, is 20% less than ;he maximum bending moment at thecenter of the conventional roll shell of FIGURE 3.

In addition to reducing the maximum bending moment :0 which theimperforate portion of the roll shell 12 is subjected, the improvedmounting arrangement of the present invention also serves theadvantageous function of providing anti-deflection to the shell topartially compensate for and offset the deflection caused by the appliedload. Referring to FIGURE 5, the dashed lines 8-37 and B-38 arrangedperpendicularly to the center axis line C-12 represent the locations ofbearing members 57 and 38 respectively, and dashed lines B-40 and B4l1represent the positioning of the bearing members 40 and 41 respectively.It will be apparent that if no load what- ;oever were imposed upon theroll shell with the excepiion of the forces imposed on bearing members40 and 41, the roll shell axis would assume an upwardly directeddeflection as indicated by the dashed lines UD12. In operation, ofcourse, the composite load L acts downwardly upon the roll shell and theresulting deflection of the axis when the shell is subjected to theapplied load L and the loads imposed by bearing members 40 and 41 assumethe curve indicated at CD12, which is exaggerated for the sake ofclarity in FIGURE 5.

It will be noted that curve CD-l2 includes a pair of peaks as at P-37and P-38 which result from the restraining action of the fulcrum-actingbearing members 37 and 38. The so-called peaks are actually so small asto be negligible in most instances, even though they represent themaximum final deflection of the center line CD-12 from the true centerline C-12.

It will be appreciated that although the force imposing means 42 and 43are described herein as fluid pressurized hydraulic cylinders, anysuitable apparatus for imposing a force upon bearing members 40 and 41may be conyeniently utilized. It will further be appreciated that theseals 22 (FIGURE 2) are resilient and subject to sufficient deformationso as to insure isolation of the suction area of the inner periphery ofthe shell 12 in spite of the deflection to which the roll shell issubjected.

Although minor modifications might be suggested by those versed in theart, it should be understood that I Wish to embody within the scope ofthe patent warranted hereon all such modifications as reasonably comeWithin the scope of my contribution to the art.

I claim as my invention:

1. A roll assembly for use in a suction press or the like apparatuscomprising:

a roll shell having normally a straight line centroidal axis thatdevelops normally a central deflection in response to a load applied tothe shell,

shaft means for the roll shell,

fixed support means for supporting said shaft means at the ends thereof,

first bearing means mounted on said shaft means inboard of said fixedsupport means and engaging said roll shell for normally maintaining saidshaft means and said roll shell in coaxially aligned and spacedrelation,

second bearing means mounted on said roll shell at the ends thereof forvertical movement relative to said fixed support means and situatedbetween said fixed support means and said first bearing means, and

force imposing means operatively engaging said second bearing means forapplying a force to the ends of said roll shell to act against restraintprovided by said first bearing means to provide counter deflection ofsaid roll shell in opposition to the deflection caused by a load appliedthereto.

2. A roll assembly for use in a suction press or the like apparatuscomprising:

a roll shell having normally a straight line centroidal 'axis'thatdevelops normally a central deflection in response to a load applied tothe shell,

shaft means for the roll shell,

fixed support means for supporting said shaft means at the ends thereof,

first bearing means mounted on said shaft means inboard of said fixedsupport means and engaging said roll shell for normally maintaining saidshaft means and said roll shell in coaxially aligned and spacedrelation,

second bearing means mounted on said roll shell at the ends thereof forvertical movement relative to said fixed support means and situatedbetween said fixed support means and said first bearing means,

force imposing means operatively engaging said second bearing means forapplying a force to the ends of said roll shell to act against restraintProvided by said first bearing means to provide counter deflection ofsaid roll shell in opposition to the deflection caused by a load appliedthereto,

said shaft means having a greater resistance to deflection than saidroll shell.

3. A suction roll for use in a press couple forming a press nip in apapermaking machine comprising:

a roll shell the centroidal axis of which is subject to deflection inresponse to a load applied to the shell,

shaft means for said roll shell,

support means for supporting said shaft means at the ends thereof,

first bearing means carried by said shaft means and engaging said rollshell for maintaining said shaft means and said roll shell in mutuallyspaced relation,

second bearing means carried by said roll shell in axially spacedrelation to said first bearing means, and

force imposing means operatively connected to said second bearing meansfor imposing a force on said roll shell to act against said firstbearing means and the restraint to the shell afforded thereby to causedeflection of the shell.

4. A suction roll for use in a press couple forming a press nip in apapermaking machine comprising:

a roll shell the centroidal axis of which is subject to deflection inresponse to a load applied to the shell,

shaft means for said roll shell,

support means for supporting said shaft means at the ends thereof,

first bearing means carried by said shaft means and engaging said rollshell for maintaining said shaft means and said roll shell in mutuallyspaced relation,

second bearing means carried by said roll shell in axially spacedrelation to said first bearing means and in radially spaced relation tosaid shaft means, and

force imposing means operatively connected to said second bearing meansfor imposing a force on said roll shell to act against said firstbearing means and the restraint to the shell afforded thereby to causedeflection of the shell.

5. A suction roll for use in a press couple forming a press nip in apapermaking machine comprising:

a roll shell the centroidal axis of which is subject to deflection inresponse to a load applied to the shell,

shaft means for said roll shell,

support means for supporting said shaft means at the ends thereof,

first bearing means carried by said shaft means and engaging said rollshell for maintaining said shaft means and said roll shell in mutuallyspaced relation,

second bearing means carried by said roll shell outboard of said firstbearing means, and

a radially directed force imposing means operatively connected to saidsecond bearing means for imposing a radial force on said roll shell toact against said first bearing means and the restraint to the shellafforded thereby to cause deflection of the shell.

6. A suction roll for use in a press couple forming a press nip in apapermaking machine comprising:

a roll shell the centroidal :axis of which is subject to deflection inresponse to a load applied to the shell,

shaft means for said roll shell,

support means for supporting said shaft means at the ends thereof,

first bearing means carried by said shaft means and engaging said rollshell for maintaining said shaft means and said roll shell in mutuallyspaced relation,

second bearing means carried by said roll shell between said firstbearing means and said support means and in radially spaced relation tosaid shaft means, and

a radially directed force imposing means operatively connected to saidsecond bearing means for imposing a radial force on said shell to actagainst said first bearing means and the restraint to the shell affordedthereby to cause deflection of the shell.

7. A roll assembly for use in a suction press or the like apparatuscomprising:

a roll shell having a given resistance to deflection and having normallya straight line centroidal axis that develops normally a centraldeflection in response to a load applied to the shell,

said roll shell comprising a first portion having an inherent resistanceto deflection of a first degree and a second portion at each end of saidfirst portion having an inherent resistance to deflection of a seconddegree,

shaft means for said roll shell having a given resistance to deflectionwhich is greater than the given resistance to deflection of said rollshell, fixed support means for supporting said shaft means at the endsthereof,

first bearing means mounted on said shaft means and engaging said secondportions of said shell for normally maintaining said shaft means andsaid shell in coaxially mutually spaced relation,

second bearing means mounted on said second portion of said shell inaxially spaced relation to said first bearing means, and

radially directed force imposing means operatively engaging said secondbearing means for applying a force thereto to act against restraintprovided by said first bearing means for causing a force couple todeflect said roll shell relative to said shaft means and in oppositionto a deflection caused by a load applied to said roll shell.

8. A roll assembly for use in a suction press or the like apparatuscomprising:

a roll shell having a given resistance to deflection and having normallya straight line centroidal axis that develops normally a centraldeflection in response to a load applied to the shell,

said roll shell comprising a first portion having an inherent resistanceto deflection of a first degree and second portion at each end of saidfirst portion having an inherent resistance to deflection of a seconddegree,

shaft means for said roll shell having a given resistance to deflectionwhich is greater than the given resistance to deflection of said rollshell,

fixed support means for supporting said shaft means at the ends thereof,

first support means mounted on said shaft means inboard of said fixedsupport means and engaging said second portions of said roll shell fornormally maintaining said shaft means and said shell in coaxiallyaligned and mutually spaced relation,

second bearing means mounted on said second portions of said roll shelland axially spaced relative to and outboard of said first bearing means,and

radially directed force imposing means operatively engaging said secondbearing means for applying a force thereto to act against restraintprovided by said first bearing means for causing force couples todeflect said roll shell in opposition to a deflection caused by a loadapplied thereto.

9. A roll assembly for use in a suction press or the like apparatuscomprising:

a roll shell having a given resistance to deflection and having normallya straight line centroidal axis that develops normally a centraldeflection in response to a load applied to the shell,

said r-oll shell comprising a first portion having an inherentresistance to deflection of a first degree and second portions at eachend of said first portion having an inherent resistance to deflection ofa second degree,

shaft means for said roll shell having 'a given resistance to deflectionwhich is greater than the given resistance to deflection of said rollshell,

fixed support means for supporting said shaft means at the ends thereof,

first bearing means mounted on said shaft means inboard of said fixedsupport means and engaging said second portions of said roll shell fornormally maintaining said shaft means and said shell in coaxiallyaligned and mutually spaced relation,

second bearing means mounted on said second portions of said shell andaxially spaced relative to said first bearing means, and

radially directed force imposing means operatively engaging said secondbearing means for applying a force thereto to act against restraintprovided by said first bearing means for causing force couples todeflect said roll shell in opposition to a deflection caused 'by a loadapplied thereto and to deflect said shaft means oppositely to thedeflection of said roll shell,

the deflection of .said roll shell being greater than the deflection ofsaid shaft means when acted upon by the force couples.

10. A roll assembly for use in a suction press or the like apparatuscomprising:

a roll shell having a first portion of a first diameter and secondportions at each end of said first portion of a second diameter,

shaft means extending through said roll shell,

said roll shell and said shaft means being subject to deflection inresponse to loads applied thereto,

fixed support means for supporting said shaft means at the ends thereof,

first bearing means mounted on said shaft means and engaging said rollshell for maintaining said shaft means and said roll shell in coaxiallyspaced relation,

second bearing means carried by said second portions of said roll shell,and

radially directed force imposing means operatively connected to saidsecond bearing means for applying a force thereto to act against therestraint provided by said first'bearing means and said fixed supportmeans, said second bearing means being spaced axially relative to saidfirst bearing means and said fixed support means such that force couplesset up thereby will deflect said roll shell more than said shaft means.

11. A roll assembly for use in a suction press or the like apparatuscomprising:

a roll shell having a first portion of a first diameter and secondportions at each end of said first portion of a second diameter,

shaft means extending through said roll shell,

said roll shell and said shaft means being subject to deflection inresponse to loads applied thereto,

fixed support means for supporting said shaft means at the ends thereof,

first bearing means mounted on said shaft means and engaging said rollshell at said second portions for maintaining said shaft means and saidroll shell in coaxially spaced relation,

second bearing means carried by said second portions of said roll shell,and

radially directed force imposing means operatively connected to saidsecond bearing means for applying a force thereto to act against therestraint provided by said first bearing means and said fixed supportmeans,

said second bearing means being positioned between said first hearingmeans and said fixed support means and being spaced axially relative tosaid first hearing means and said fixed support means such that forcecouples set up thereby will deflect said roll shell in a first directionand said shaft means in a second direction.

12. A roll assembly for use in a suction press or the like apparatuscomprising:

a roll shell'having a first portion of a first diameter and secondportions at each end of said first portion of a second diameter,

shaft means extending through said roll shell,

said roll shell and said shaft means being subject to deflection inresponse to loads applied there- [0,

fixed support means for supporting said shaft means at the ends therof,

first bearing means mounted on said shaft means and engaging said rollshell at said second portions for maintaining said shaft means and saidroll shell in coaxially spaced relation,

second bearing means carried by said second portions of said roll shell,and

radially directed force imposing means operatively connected to saidsecond bearing means for applying a force thereto to act against therestraint provided by said first bearing means and said fixed supportmeans,

said second bearing means being positioned between said first bearingmeans and said fixed support means and being spaced axially relative tosaid first bearing means and said fixed support means such that forcecouples set up thereby Will deflect said r-oll shell in a firstdirection and said shaft means in a second direction, the deflection ofsaid roll shell being greater than the deflection of said shaft meansregardless of the magnitude of the force imposed by said force imposingmeans.

13. A roll assembly for use in a suction press or the like apparatuscomprising:

a roll shell having a first portion of a first diameter and secondportions at each end of said first portion of a second diameter,

shaft means extending through said roll shell,

said roll shell and said shaft means being subject to deflection inresponse to loads applied thereto,

fixed support means for supporting said shaft means at the ends thereof,

first bearing means mounted on said shaft means and engaging said rollshell at said second portions for maintaining said shaft means and saidroll shell in coaxially spaced relation,

second bearing means carried by said second portions of said roll shelloutboard of said first bearing means and inboard of said fixed supportmeans,

radially directed force imposing means operatively connected to saidsecond bearing means for applying a radial force thereto to act againstthe restraint provided by said first bearing means and said fixedsupport means,

whereby a force supplied by said force imposing means will set up forcecouples in said roll shell to deflect said shell in opposition to a loadapplied thereto.

14. A suction roll for use in a press couple forming a press nip in apapermaking machine comprising:

a roll shell the centroidal axis of which is subject to deflection inresponse to a load applied thereto,

said roll shell having a perforate portion of a first diameter and otherportions of a second di' ameter at each end of the perforate portion,shaft means extending through said roll shell and hav ing suction glandmeans in axial alignment with said perforate portion,

fixed support means for supporting said shaft means at the ends thereof,

first bearing means mounted on said shaft means and engaging said rollshell at said other portions thereof,

second bearing means carried by said other portions and spaced axiallyrelative to said first bearing means, and

force imposing means engageable with said second bearing means forproviding a force couple with said first bearing means to deflect saidroll shell in opposition to deflection caused by the load appliedthereto.

15. A suction roll for use in a press couple forming a press nip in apapermaking machine comprising:

a roll shell of the centroidal axis of which is subject to deflection inresponse to a load applied thereto,

said roll shell having a perforate portion and other portions at eachend of the perforate portion,

the diameter of said perforate portion being greater than the diameterof said other portions.

shaft means extending through said roll shell and having suction glandmeans in axial alignment with said perforate portion,

fixed support means for supporting said shaft means at the ends thereofoutboard of said roll shell, first bearing means mounted on said shaftmeans and engaging said roll shell at said other portions thereof,

second bearing means carried by said other portions and spaced axiallyoutboardly relative to said first bearing means and axilly in'boardlyrelative to said fixed support means, and

radially directed force imposing means engageable with said secondbearing means for providing a force couple with said first bearing meansto deflect said roll shell in opposition to deflection caused by theload applied thereto.

16. A suction roll for use in a press couple forming a press nip in apapermaking machine comprising:

a roll shell of the centroidal axis of which is subject to deflection inresponse to a load applied thereto,

said roll shell having a perforate portion situated in the middlethereof an imperforate portion at each end thereof,

the diameter of said perforate portions being greater than the diameterof said imperforate portions,

shaft means extending through said roll shell and having suction glandmeans in axial alignment with said perforate portion,

said roll shell having a given inherent resistance to deflection andsaid shaft means having a substantially greater resistance todeflection,

fixed support means for supporting said shaft means at the ends thereofoutboard of said roll shell,

a pair of first bearing means mounted on said shaft means and engagingrespectively said roll shell at each of the imperforate portions thereoffor maintaining said roll shell and said shaft means in mutual spacedrelation and normally in mutually coaxial alignment,

a pair of second bearing means carried respectively on each of saidimperforate portions outboard of said first bearing means and inboard ofsaid fixed support means,

said second bearing means being in radially spaced relation relative tosaid shaft means,

radial force imposing means engageable with said second bearing meansfor imposing a radially directed force thereon said first bearing meansacting as fulcrum to set up a force couple with said force imposingmeans to deflect said perforate portions in the direction of the forceapplied by said force imposing means and to cause deflection of saidimperforate portion in a direction opposite to the direction of theforce supplied by said force imposing means,

said shaft means being caused by said force imposing means to deflect inthe same direction as the force imposed thereby,

the axial spacing of said second bearing means relative to said firstbearing means and said fixed support means being such that the rollshell deflects more than the shaft means for any given force applied bysaid force imposing means.

17. A press couple for use in a papermaking machine comprising, incombination:

a suction roll,

a pressure roll for applying a load to the suction roll to provide apressed nip therebetween,

said suction roll comprising a roll shell the centroidal axis of whichis subject to deflection in response to a load applied thereto by saidpressure roll,

said roll shell having a perforate portion and a pair of imperforateportions respectively at each end of the perforate portion,

said perforate portion having a diameter which is greater than thediameter of said imperforate portions,

shaft means extending through said roll shell and having suction glandmeans in axial alignment with said perforate portion,

fixed support means for supporting said shaft means at the ends thereofoutboard of said roll shell,

first bearing means mounted on said shaft means and engaging said rollshell at the imperforate portions thereof,

second bearing means carried by said imperforate portions and spacedaxially outboardly relative to said first bearing means and axiallyinboardly relative to said fixed support means, and

radially directed force imposing means engageable with said secondbearing means for providing a force couple with said first bearing meansto deflect said roll shell in opposition to deflection caused by theload applied thereto from said pressure roll.

18. A press couple for use in a papermaking machine comprising, incombination:

a suction roll, a pressure roll for applying a 'load to the suction rollto provide a pressed nip therebetween, said suction roll comprising:

a roll shell centroidal axis of which is subject to deflection inresponse to a load applied thereto,

said roll shell having a perforate portion situated in the middlethereof and imperforate portions at each end thereof,

the diameter of said perforate portion being greater than the diameterof said imperforate portions,

shaft means extending through said roll shell and having suction glandmeans in axial alignment With said perforate portions,

said roll shell having a given inherent resistance to deflection andsaid shaft means having a substantially greater resistance todeflection,

[fixed support means for upporting said shaft means at the ends thereofoutboard of said roll shell,

a pair of first bearing means mounted on said shaft means and engagingrespectively said roll shell at each of the imperforate portions thereoffor maintaining said roll shell and said shaft means in mutually spacedrelation and normally in mutually coaxial alignment,

a pair of second bearing means carried respectively on each of saidimperforate: portions outboard of said first bearing means and inboardof said fixed support means,

said second bearing being in radially spaced relation relative to saidshaft means,

radial force imposing means engageable with said second bearing meansfor imposing a radially directed force thereon,

said first bearing means acting as a fulcrum to set up a force couplewith said force imposing means to deflect said perforate portion in thedirection of the force supplied by said force imposing means and tocause deflection of said imperforate portion in a direction opposite tothe direction of the force applied 'by said force opposing means toopposing means to oppose the deflection of the perforate portion causedby the load of said pressure roll,

said shaft means being caused by said force imposing means to deflect inthe same direction as the force imposed thereby,

the axial spacing of said second bearing means relative to said firstbearing means and said fixed support means being such that the rollsshall de-flex more than the shaft means for any given force applied bysaid force imposing means.

(References on following page) References Cited by the Examiner UNITEDSTATES PATENTS 4/1931 Berry 16 237 1 3/1943 Berry 162-371 5/ 1944Goodwillie et a1 1 62-37 1 3/1958 Byrd 6 8256 Shapiro et a1 182 Moore100-90 Justus 1'00155 Justus 100-155 LOUIS O. MAASSEL, Primary Examiner.

1. A ROLL ASSEMBLY FOR USE IN A SUCTION PRESS OR THE LIKE APPARATUSCOMPRISING: A ROLL SHELL HAVING NORMALLY A STRAIGHT LINE CENTROIDAL AXISTHAT DEVELOPS NORMALLY A CENTRAL DEFLECTION IN RESPONSE TO A LOADAPPLIED TO THE SHELL, SHAFT MEANS FOR THE ROLL SHELL, FIXED SUPPORTMEANS FOR SUPPORTING SAID SHAFT MEANS AT THE ENDS THEREOF, FIRST BEARINGMEANS MOUNTED ON SAID SHAFT MEANS INBOARD OF SAID FIXED SUPPORT MEANSAND ENGAGING SAID ROLL SHELL FOR NORMALLY MAINTAINING SAID SHAFT MEANSAND SAID ROLL SHELL IN COAXIALLY ALIGNED AND SPACED RELATION, SECONDBEARING MEANS MOUNTED ON SAID ROLL SHELL AT THE ENDS THEREOF FORVERTICAL MOVEMENT RELATIVE TO SAID FIXED SUPPORT MEANS AND SITUATEDBETWEEN SAID FIXED SUPPORT MEANS AND SAID FIRST BEARING MEANS, AND FORCEIMPOSING MEANS OPERATIVELY ENGAGING TO THE SECON BEARING MEANS FORAPPLYING A FORCE TO THE ENDS OF SAID ROLL SHELL TO ACT AGAINST RESTRAINTPROVIDED BY SAID FIRST BEARING MEANS TO PROVIDE COUNTER DEFLECTION OFSAID ROLL IN OPPOSITION TO THE DEFLECTION CAUSED BY A LOAD APPLIEDTHERETO.